1. Field
The embodiments relate to an image forming apparatus for saving a toner used for image forming, and an image forming method thereof.
2. Description of the Related Art
As a result of the development of the electronics, computers and peripheral devices such as printers and scanners are prevalently used. In particular, manufactures of the printer are increasing development. Recently, the use of laser printers which are more effective than existing dot printers or inkjet printers in terms of the printing quality, the printing speed, and the noise in the printing is gradually increasing. The laser printer is a printer which applies a toner to a photoconductive drum using a laser beam converted to an image signal, transfers the toner on the surface of the photoconductive drum to a printing paper, and fuses the toner onto the printing paper using high heat and pressure.
To print the image, the operations of the laser printer largely include charging, writing, developing, transferring, and fusing. The charging generates the (−) charge on the surface of the photoconductive drum using a corona discharge by applying high voltage (about 7000V) to a charger. The writing forms a latent image by projecting the laser beam to the surface of the photoconductive drum of the (−) charge generated and removing the (−) charge in the character shape. In the developing, toner particles of the (−) charge are attached to the latent image on the surface of the photoconductive drum. The transferring attracts the (−) toner particles formed on the drum surface toward the paper by applying a transferring voltage to a transfer unit when the paper passes between the photoconductive drum and the transfer unit and generating (+) charge on the other side of the paper. Next, the fusing completely fuses the toner on the paper by applying appropriate heat and pressure. Through these processes, the image is formed and output on the paper.
Recently, color laser printers which realize colors using the laser method are supplied. The color printer generally realizes a color image using the toner of the four colors CMYK. To print the vivid image, the printing job can be processed per toner color using four photoconductive drums. To project the toner of each color to the accurate location, the transferring process can be carried out in two steps using an Intermediate Transfer Belt (ITB).
Meanwhile, when printing or copying an original document of the density greater than a certain level, or when copying the document while a cover of a scanner is not closed normally, a dark image unexpected by a user can be printed with the serious toner consumption.
In this regard, a toner saving method for preventing unnecessary toner consumption is necessary.